The objective of the proposed research is to develop a series of highly improved recombinant bacterial larvicides for controlling the mosquito vectors of major human diseases including malaria, filariasis, dengue, and the viral encephalitides. These bacteria will be significantly more cost-effective than Bacillus thuringiensis subsp, israelensis (Bti) and Bacillus sphaericus (Bs), the active ingredients of current commercial bacterial larvicides used in vector control. In addition, these recombinants will be much less prone to induce mosquito resistance, which has already developed to B. sphaericus in Culex populations in Brazil, China, and India. Preliminary studies show that the production of high levels of the Bs2362 binary protein in Bti results in a recombinant strain tenfold more effective than the parental strains from which it was derived. This demonstrates that highly improved bacteria can be engineered for use in vector control. Despite these encouraging results, the development of recombinant bacterial larvicides is plagued by several major hurdles including low returns on investment, limited market size, and additional regulatory burdens imposed on recombinant organisms that result in long product development times. The present project is a collaboration between the University of California, Riverside and Valent BioSciences of Libertyville, Illinois, that will combine the expertise of both parties to accelerate the development highly improved bacterial larvicides for vector control. Through focused engineering research, a series of much more effective strains of Bti and Bs based on Cry, Cyt, and Bs mosquitocidal proteins will be developed and commercialized that also meet U.S. regulatory requirements. Improved strains using Bs as a host cell will be developed primarily for control of Culex species (vectors of filariasis and West Nile Virus) breeding in semi-polluted and highly polluted waters, whereas Bti will be used as the host cell for control of Aedes species (vectors of dengue) and certain anopheline vectors of malaria. This collaboration has the common goal of having new products based on these recombinant bacteria on the market within five years, sooner if possible.